Wave movements in the sea and in large inland lakes constitute a potential source of energy that has scarcely been exploited so far. However various suggestions have been made to use the vertical movements of the sea for producing electrical power in a generator. Since a point on the sea surface makes a reciprocating vertical movement it is suitable to use a linear generator to produce the electric power.
WO 03/058055 discloses such a wave-power unit where the moving part of the generator, i.e. the part that corresponds to the rotor in a rotating generator and in the present application called translator, reciprocates in relation to the stator of the generator. In that disclosure the stator is anchored in the sea bed. The translator is by a wire, cable or a chain connected to a body floating on the sea.
Ideally the floating body is located vertically above the generator on the axis of the translator as illustrated in FIG. 1 of that disclosure. However, the floating body is exposed also to lateral forces from the waves and from the wind. Therefore the floating body can drift away from that ideal position and will normally be located at a distance there from. As a consequence the wire connecting the translator and the floating body will not be aligned with the axis of the translator. This might cause side forces to the translator resulting in that it will not be centred or/and it becomes inclined, which will disturb the operation of the generator.
This can to a large extent be avoided by journaling the translator in the stator. However, when the wire is inclined the side forces in that case will result in a high load on the journals and disturb the operation.
In order to reduce this problem it is known to provide guiding means that guides the wire towards an axial direction when connected to the translator. Such a device is disclosed in PCT/SE2008/050964. The disclosed device, however, might cause wear on the wire.
The object of the present invention is to solve the above mentioned problem and thus provide a wave-power unit where the generator will operate properly irrespective of the relative lateral position of the floating body, and simultaneously avoid the drawbacks related to known technique.